I was speaking to another caravan owner yesterday and it transpired that when his van is not connected to the car or has no 240v cable connected to it, if he switches his 12v. switch the leisure battery runs the fridge. None of my last three caravans were wired up this way.

Is this normal or just down to what the different caravan manufacturers decide to do?

It may provide power to the control panel and fridge light but it's unlikely to power the fridge cooling system unless wired up incorrectly. The 12v supply may make the fridge switch over to gas automatically in such a way that the owner is unaware of what is making the fridge cold.

To answer the question; no, my fridge doesn't run off the leisure battery.

Oh I wish!!!! I've expressed my thoughts about dragging caravan refrigeration into the 21st century... I would love a compressor fridge! The sheer inefficiency of using heat to generate coldness is a joke... My compressor fridge on my boat draws an average of 0.8Ah (It fires up at 4amps and runs for about 5 mins every 25 mins =4x(5/60)x(60/25)).

With my old 90W solar charging, I could survive about 7 days off grid with 3x110AH batteries, so on the typical caravan layout with a 100W solar panel and 1x110AH battery, it's just over a couple of days off grid...

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Oh I wish!!!! I've expressed my thoughts about dragging caravan refrigeration into the 21st century... I would love a compressor fridge! The sheer inefficiency of using heat to generate coldness is a joke... My compressor fridge on my boat draws an average of 0.8Ah (It fires up at 4amps and runs for about 5 mins every 25 mins =4x(5/60)x(60/25)).

With my old 90W solar charging, I could survive about 7 days off grid with 3x110AH batteries, so on the typical caravan layout with a 100W solar panel and 1x110AH battery, it's just over a couple of days off grid...

I need at least 7 days off grid! How can even the best compressor fridge meet that requirement, with only a single 110Ah battery and preferably a 100W panel.

Failure to meet that requirement is a red line when buying a van as far as I am concerned, and I suspect that I am not alone.

Even an average of 0.8a/h equates to 19a/h a day of which say 10a/h will get used overnight when the panel isn't operational. Which means that your solar array has to provide around 25a/h during daylight to run the fridge and put back the energy that the fridge took out of the battery overnight. Not forgetting any other energy that gets used either during the day or during the night, which depletes the battery overnight and has to be restored during the day.

You've also got to take into account the days that you don't get wall to wall sunshine, shading or non optimal orientation of the panel so you need enough battery capacity to keep you going. As a battery shouldn't be discharged below around 50% of it's capacity if you want to ensure it's longevity you'd need to ensure adequate capacity for extended off-grid operation.

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Compressor fridges are noisy and only work with electrical power. The noise right in the bedroom would be a big fat NO for many? {I was in a hotel at the weekend where the fridge was a 240V absorption one. I'd not have wanted a compressor in there. Hotels would fit the cheapest units if it were acceptable to their customers but use absorption for a good reason.}

NB Caravan absorption fridges were gas only for many, many years before mains and 12V heating elements were added to the design. Until the last few years, few caravans had solar panels as standard. But you'd need a much bigger battery and panel to keep up!

The compressor one (using nasty fluorinated regrigerant gas) does only consume 400 Watt-hours in a day (0.4kWh). It also holds more foodstuffs. And emits 40dB(A) of sound.

The 3-way one uses 2,500 Wh on mains electricity but is silent 0dB(A). On gas it uses 270g per day which I make to be 3.75 kWh :eek: (1kg propane = 13.9 kWh). So the (in)efficiency of absorption is unquestionable.

To try to put the 40dB(A) noise into some context dishwashers seem to be between 43 (expensive Miele) and 49 dB(A) (Hotpoint). My indoor unit of a split pack air to air heat pump is 21dB on the lowest fan speed (not quite inaudible) up to 42dB(A) at max (and that's really quite noisy). To have that noise switching on and off in a caravan through the night would be torture!

You guys carry on... the compressor fridge on the boat is running about 8' from my head (closer than the van fridge is) and I don't hear it... and before someone comes up with "the boat is better built than the caravan" it sits on a half inch ply base (floorboards) with a big resonant space to the hull behind... You guys spend your money on the gas, if I could get a compressor fridge I'd be on it like a flash, but I'm happy to let you guys keep on doing the same old thing...

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Normally the fridge will not run off the leisure battery. However, an ingenious person could rig up connections via the 13 pin plug so that it could do so - but obviously, as mentioned, not for long periods. This may be useful for longer ferry trips?

You guys carry on... the compressor fridge on the boat is running about 8' from my head (closer than the van fridge is) and I don't hear it... and before someone comes up with "the boat is better built than the caravan" it sits on a half inch ply base (floorboards) with a big resonant space to the hull behind... You guys spend your money on the gas, if I could get a compressor fridge I'd be on it like a flash, but I'm happy to let you guys keep on doing the same old thing...

Part of the reason I originally posted was that when setting off for a trip I noticed that when my Freedom shed was connected to the car WITHOUT the engine running, and I switched on the fridge to 12v. the switch lit up showing there was a 12v supply ????

Now, I never normally connect up to the caravan that way. It has always been a case of switching on the fridge BEFORE connecting the car, thus I would not see if the 12v switch light was on or off.

However, on carrying out research I found a blog and you can read it HERE

Part of it says :-

Now we come on to the Freedom. It has the two pins on separate wires coming into the van, but then they are connected together, via two extra wires (power and earth) soldered to pin 10 wire at the 12v socket for the fridge and the caravan loom near the psu/leisure battery/pin 9 wire. This means the fridge can be powered by both pins and work from the leisure battery even when the car is off! If your car battery was flat, then the current wiring means the starter motor would pull it’s power from the leisure battery through wiring not suitable for that draw, only a fuse should prevent that happening. It doesn’t take a genius to realise that this is not a good idea, and it seems strange that it’s been wired up this way.

A 12v compressor fridge uses around 4-5amps when it running BUT it probably only runs for 20% of the time therefor it's average consumption is about 1a/h. As it runs for 24 hours it will use 24a/h (=288watt hours) in a day. You can then then do the sums (or math as the Yanks would say) to work out how large a battery you'd need to keep it going overnight and for days when the sun don't shine and how much energy you are going to get from a 100w solar panel during the day to charge it.

You need a lot of solar power and a lot of battery capacity (or to be very frugal with your consumption) to be self sufficient and chewing through at least 24a/h a day just for the fridge means you wont have a lot left for other stuff.

Absorption fridges may not be everso efficient but it's easier to store and transport LPG than it is to generate or store electricity, especially if you've got space and weight restrictions

However, since we always try to go to CL's with a EHU my choice would be a compressor fridge, but I see your point regarding the absorption powered fridge. It would be nice to have a choice if the manufacturers offered it.

I have a compressor fridge in my hightop motorhome. The reason a compressor type was fitted is because the Transit has a vertical body strengthening bar right behind the fridge and that means that the absorption type vents can't be cut in the body. On it's sister layout by the same people the fridge is further back in the van and the plain metal panel allows the vents to be cut.

This is the second van we've owned of this type. The original had the same Waeco type fridge and it had a noisy 'click' every time the motor switched on or off. The motor itself was just a quiet hum. The click did sometimes wake us up. On the latest van you can hardly hear the click as the motor switches on and off and it hasn't woken us at all. Not sure if it's technical progress in producing quieter fridges, that this time we just hit lucky, or we're deafer than we were a decade ago.

As to battery duration with a compressor, our experience is that without EHU or solar a fully charged 100a/h leisure battery lasts for about a day before it'll no longer run the fridge.

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Absorption fridges used to be popular in boats as well as caravan until the safety regulations were tightened up on our inland waterways. Unlike a caravan, it is not desirable to provide drop holes in case of gas leaks! Also, the naked flame can provided an ignition source in case of a fuel leak in the boat, as I know from experience.

Boats now use compressor fridges. I have slept with my head next to the fridge in our boat and the noise did not disturb me, despite it being fitted with a fan. However, battery use is an issue. We have a 60 W solar panel fitted and can last for three or four days with two 110 Ah batteries. After that, we need to run the engine or connect to shore power to recharge.